SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f57dea56821f5366a57a05a39e07af90d990958c7efa575f70ad5b6477ec4205' 
  AND token = 'oi+hMThxLVIYSls4VVQ0TtpZthNxYy/unZmLze2+XTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}