SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc94175d07c77efc8f560dfd48a9304ef89485fc69a909b254a7ce4082df494a' 
  AND token = 'tAMdAKokISsXOxar+2xtL+YFZCdGx6VDT3nRLxRzGhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}