SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f040d0ff9b6689b3c058b210884292736202a40efd53c291e088ec08c7998f3e' 
  AND token = 'pH5SfOSeJrcioPyADcvOYAIYIjijboXNJNTQam0uu54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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