SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b328a9671a52ccc81815144d7340204ccb3c6847bbf25d5ee11ffa2a685a8633' 
  AND token = '/IpBp1KnXxXPjRYiLqNngARiaCkr0IzWKX5belLb45o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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