SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6c78cc28fdf2456e02baf783a41af235f32d2323b73d199928498576e74338ab' 
  AND token = 'NXXpC87sqvir706/tFMKY0AW/JsyWgh7hgyRB7DVbfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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