SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1370f8d7a4d5c7629a1fb7dc808e8e3862b7bf778a96410cc254800bc2ddb08' 
  AND token = 'BIxv1nXwuu66Qsvjc3PrwAV3aHzauj/O+zxMIkEgG5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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