SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e71efb9118202fcfcba8fe074a46e7048a65d1f10a7d496382b39f3ec896f7' 
  AND token = 'cr2Brltg9F9kG5OZL9jdpzKC7EZmnv92RMwTBh0w5J8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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