SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67ca058ccae6657ea7345e6913a9af894bddc9f8db430026791851e4f9297596' 
  AND token = 'eYi831HHvtu+CVdSvYWX5hA08P41W9ZVe1t7Vbj6NJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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