SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df885cbbcafa3f3b34ea81809b6a1ff9b2303ca235b374468611decaffc9d34b' 
  AND token = 'iH8YaLqmZZEzecFHS2+p/nuW4lVfi5DthQG2rBwg7Ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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