SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5e6b53b0ba01afca90026790c0952e0465838c21a6325d2f6666742e88b1c748' 
  AND token = 'ophk2oyr/EEasDnJw0QyaWYJlki+oWyj4ptKsxZopIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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