SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b740e012a73d9a213f5c0cd0bc48ee952552817a1848a582acb7421792c07149' 
  AND token = 'j+A9971WPWXtu6nUQNxelvkkRuAeUZobuJDtYjwKrIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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