SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a34229c98f9aefa567e71d080d3bb9d40a44a356b14bc8b0503acf0d16b3854' 
  AND token = 'gaN3b/5lcBPysh6EfZywiVq9oOG8rGd9lWQAfU20m8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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