SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c419d9220b15c166a74d13bcda147c55bf515281f762a82e94725e5b03525ed' 
  AND token = '/X9zVIgVllX2HmToU/ZJmpC4QI4Py1hX6liuZB25YsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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