SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b793dbdfcbfa40d355c0a914412be0aa4f541ded76ff3eab699c39f480207a68' 
  AND token = 'Vam0wASE9juOqLC0kL2DB64RCZBvBqs9CPX4AxCW32U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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