SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9fb67a846d8d6427d0fc60388e4f279a98150f252abf49466dbe784bef171d7' 
  AND token = 'oOhcpH9746u6DRkx9Dvn2IIqU2Ty+bMrrBafafkK2kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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