SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '596c3d320350e71843964162a04386a2326897cba2560721169d2b28c04065e2' 
  AND token = 'mo7DJQBGUAxXwwBI5vltAvwfKM3fL7Ok0C6MHc0MOV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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