SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99c50a8d03b20b0e1ddec035b32776165e489002f2541fbf9ccc9781268dfffa' 
  AND token = '8LtLhA2QHv2XqKbrBzpKO1g5MEHZnT4q/sVIFXRLJRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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