SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ad10b718e2b4d7be6f198afac64de52a83f459968f4128e7995d0763752a08e' 
  AND token = '+SQBUlFsX6m/G+0c0rDGso563tVSOASh+wjmxwQfuw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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