SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fe535289509761a6117c0658ff9176b1ebe0840d2263ac823d921c3d91a9db7' 
  AND token = 'WjIfNYVbHMiJPPMRiwIUutigzJv9UPKC8Pl/SdnuzgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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