SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ad27412472540930ff536c85bf78ef4afd75d8db86c1ac8262853cd95ac840' 
  AND token = 'mNENFW4vtk/jyFamtnFuZPwDZKU3iQBTaDgHMO4icQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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