SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7585c4731eec9a39c7036b35507f9a94cdf52de2fe04947d70eaeff4560e32f1' 
  AND token = 'FnCMsdvDoLPRwAmjzESioW21kyxlasPZbpTTqcD/yXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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