SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f60fa6653e930fa44d4b1cc5b8ffab2a9027676a3569b00cf7efda10b441a8ba' 
  AND token = 'UbPjSzgc+4WqdI87l8+lcBISHqhuACwsHRrRRBcLc2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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