SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91ce672cb8371bdfeab605b665e841429a37ac70787ce8e4ade4b56e12a73016' 
  AND token = 'qOI5iXGsSbVh8MkIzcfDX6QzAgxcBNM8UnI8IIa5tko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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