SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6be07633f8bc7599c4015618462edeb961d448b14bf0ece883aa18d2bd7febc' 
  AND token = 'v+jmBdxxrduKIRLI0MaeIE6WOWJNccKDTXNC3SjiKJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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