SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b38e0926792b949a548598efc5b30d28c95137c83fa23ffadb55d47c56ae364' 
  AND token = 'ya6FJFf4svACZFEv/iCQBGj/Ib3NGoyZqNF0tvhm61M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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