SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b3ffb24ccbf7292adceec56e14753244054408328a3edce426136b011478a6f' 
  AND token = 'QZ2qGw83VIlBsTeXZJbRu2uuJDXsymbJsz/HLXq7fpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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