SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45dc9494f7d39256893e58bcd50babefbad928ed9ab8d6a5521621b187c071f2' 
  AND token = 'GEfFtDa/QnrjcxLA0JCXhBkGpqXgWt2+T512uNZt0Qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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