SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74f838aac2e479368193591abb98a6cb30aab2495c1d149b96558083971423c3' 
  AND token = 'JdjSHAEwwWSazjXbSxhsHdFH9LzGsj5Uchy1RSFsg1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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