SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '781362934d43c6661b2c0525dc66459cd68a7a3587d92392977803e73c6c53bd' 
  AND token = '1SrltO9keIquKZyrkjf1ZcO7d5GIePicllCmn882sdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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