SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '843091117eb74028c12953d435d0c772471a35cbc5cbfd8ca2a57f9db9be9d41' 
  AND token = 'yQTOwmBclk9P8QOIqCKIU7Mcay5q5YRh2QZ6S+pRpVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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