SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e93cf674826832799289f366721792b477bc2c70923ea062b2a839af181aaea3' 
  AND token = 'W6dLHTN4MhWk4spP2KEyXvMukbjC6IiytkGoXycv5j0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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