SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fad2b6e823a0fa64effd6d10a1608677adf2f44952061aa66fafae61f367b64' 
  AND token = 'z2lJhp3JCZLVhncIxO3mb1HgDuXWRMs5gJfOa7qR0CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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