SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a6fd2113cd8323a44985d9334e743898887fd98318da9042552b86e8507a058' 
  AND token = 'X8IrrCktrHew07xDAgaCxeddttUMErhwHlwStlgUa04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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