SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '567d3b344667633be515365273cf8e70281330bb04c2a499c9f94256c65c50a1' 
  AND token = '3jf0qfB/KfcC5PGZzEoZMfOMYnrJvbh3a3X4gSK8gxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}