SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92beba0f4cbe15b1dae64c6daca493918796708f66176fe059c20db40dbb5eb' 
  AND token = 'bA4sRnYQ/X6LY1hB3rqXPYHgpZmojICzRHZ6UFDwBoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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