SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aecca12a7661275e1d081bbd27d9f10d72fdc2de91654830fd37ef1af262acf9' 
  AND token = 'ybKR27NEsVIdjI4FDfBIZd250ft6ROyWGOxFKMaTcqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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