SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb9263b859e8f61a23ac3046d040358a2968dedd539acad655557ceb40170ef7' 
  AND token = 'uGWJN+DtHaPDmezZ3YTFNZguoMhnTf+guqQneuXnyog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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