SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abced9d74348455fcb526e27081272e52caa92fe6ad15c4373f3c7c2aec10c77' 
  AND token = 'PJyczvo42zFMOU1SDyS0yOlUQc8W/0rL0dper9YZl7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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