SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888eea86043be317dcd74919b75845c9daced68d3ea93acfa6120aee9f3a1192' 
  AND token = '5YcQ3sbVuDfYabWXJwQXpggSCkua+yHZZSn4Zwa+X20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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