SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a6d33ebcc5271253fa867d576d8e061152fe879d44b9f2ab4d3a0c2904a9956' 
  AND token = 'ngmcsDsHjKHLvYVo/THXnX8AixTrQPRzDeQ2ptmf4cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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