SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c101e57e6e3bc44a88257dd3fdbbc0815f1b3674ac8396af0b9d50a09d755ea' 
  AND token = 'LhMr5PsPL7Pv5IR4gQsH4wPzdDR6qntVWE0bB/Tezaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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