SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f64ad487d1db750c6cb3ba790e6dec2c53bbe8499c1a436215e9174724f852e5' 
  AND token = 'QWFMjPAWNbkw4aBASz8WKhRc7ImGoRvqZQptPCZU+PY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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