SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2786a64de7e35be868cd649ba21c3d4aff1c8d9a743ffeadd3ed47bf3ff1769' 
  AND token = 'us5pKFJKlP2sLo3EhHBqY4zn8FgiOSjC7mHCpPmeTbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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