SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '863de08098f5f3922942e42ede77addcaa38c04b670954481321aaef783bf719' 
  AND token = '/9+h1WwZ2pw23NZPSkNfOlqDrdfIoB2SDOKPj9XA0xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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