SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1df0d31a5e357a5024f20abe6114d2dc8de27994aaa952d418d2e2b7c9859c1d' 
  AND token = 'rJXaNlnn7xev3MpUKfAUlovExumgl8uCSG42uH23eb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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