SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f187f8d38d12301b8f66dee986ac9a66a153885011c64c437d56d1b777f6b8ad' 
  AND token = 'gOizSV5KJ+ysSsnmirBTt5uIBn9Q8gcZYbv6UBQAdW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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