SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cffab665273059627d054cbd03f02c071a15efa276e3cfedea344d51dddf172' 
  AND token = 'xxi4NGkYss64mpBSjL4xn2/0zZRHMPIbQ4bm0IONMAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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