SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc38d37830456bc2bb379f5b3fbaf83de01d6f370e16b0bd7712b312792b95b' 
  AND token = 'zro3YasdPTdQo7HSa2oTt99b+Hb9VprpoZXMjEchndg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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