SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84be2619ae59bd53c831245d9082f8a618eca96c2096fd1a368d494ed05fc70e' 
  AND token = 'PguTZ+9SSYKSYJ9uGNTLHciSwhq37/Fqpcm3Pkef1Bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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