SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '120eede239f623d66e5e66933356bc778827cb014600b0991ef68dddb258968e' 
  AND token = 'arbKjje9gEurZ+dstMMI0B9EmeRGwFf8b/C56AKHnIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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