SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e99dffa0f09b47b90f6f14bcd77cec2704f9c84e6b65d950b7859aeacf518d5d' 
  AND token = 'JmLEmeNRfIkR09JlmnvA0Itjix7sP+58MRpJKU6gih4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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