SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '999b3b858ec35239f77ae1d51f788ecedd5bcadff9cd628f063cf6dc93993ee5' 
  AND token = 'situ1gzZgxmka5/XkAAnXA1eTsQGvFQyLOvT3fYXz+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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