SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fa03685a2c3d28292a03b476cf64be1bf5a47591c2bf9c1f66787bd58e9243b' 
  AND token = '/Gg4G5IyM3TtKwn+IsTw4nR9wBdzeXtCmL2nKSVIwi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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