SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4cf5359c7dcf1a52320902ee36a3a2904787dc2fd66e8831f513255ee61070ec' 
  AND token = 'sNAt92r6ESjSKf90AT5xYvg3gxGW44jiXWFVuMEznzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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