SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae3d91f33a093501f8d49960e25ac671cf9174b8107ccb82c665bfa4db3a3ba1' 
  AND token = 'ncIDiYayvoE6C57oBEWP7JCxstODvI4zghTGFfaSCxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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