SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47548da24a4b3081af31a730526869f52aa299b65cae67be9adeb0ffe6bd8419' 
  AND token = '9YWXVcxNV+mDVk129nenTEga2SxwZSCt1g4+JHm/V7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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