SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85719fe54fa06c4efad8e5d393cbd5a38a6abbf4ba41ee480ad2cf22b7bc8172' 
  AND token = 'ZkBFfgdxZEQtClJUgmFtnKH7YgrYGQhhWN9+LBs5MpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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