SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a418844a9be86f630a79507cc84bb7acd3c924c405c91be2975f262c25334045' 
  AND token = '5RMma0rcv4uPwm2Qph7TcvjQVKAYAy6bINeKoLsBns8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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