SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fcd6f35fc24334bdeab080e938364af630e4a3330e07024d5e94fdee5348a379' 
  AND token = 'PSa0aye6tNehXugYUbJgQfvlvBIPS1GALuu2HFIdDaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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