SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf9129f33272edebecc00a58a561d44f7e3ba382b94376fcfb45e5803d9476ae' 
  AND token = 'FkusJwITLuc7JScybIxBMHjTHtpUQJ+4byyWRlrqwt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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