SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77bb22ffd4f685cf4d2189444e8f8019d41cbe619675709620c93eabe5ebc91c' 
  AND token = '36djO/rW/VnQRikxKbZK7GtKFbL7DlQJhauPFY6ROFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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