SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef7275ef2c5fcba2fa067af9aa6a0f4ff33eb52bba6cc0e07a21811be9132ad9' 
  AND token = 'BSrX9KBQa78IkCWymdezBapIF6WEiaaHhR+P46g5IbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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