SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '117bd5a1defc803df95822ff42e42d9fcb4b65b0a1b4d367c0940f4baaa79748' 
  AND token = '9hF0Uv5ewKYbpKfCYEC1TXuKzaMb8f9+MsL6zAsUEWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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