SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e361ba8892af37b81aba309caeae471d864ff3fe798d87b43619b01bee6e9e43' 
  AND token = 'PeQVTMyjOSZqRf6zcOMB6rD6n2JFiOrEtCR2uVefrRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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