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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5ec4b0a1e1cf65ddc27b2c8fb539b86e7cdc073010c42ce5636b9ee8f0ad147' 
  AND token = 'ffFHwvt50O/4OZRe0Z49m+ZRAyjxoUItq31U/OB/BbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}