SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fab7c8476b7af97917b535cfe5262ba6496876d012ef75912bc0c57802f9799' 
  AND token = 'ffTVngspuRSy+h3LqGGBEipWxb9a58l2dI0NXpMRHm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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