SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd45942ad5fc0bc448007eaa3ced6a272ad555e9d3d9a8758c517d3ec0a2b215' 
  AND token = 'E9aeZB56Ua4sY/PS1Epw8KFB78taFrIjto1uFtBZAnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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