SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7a8868d8c3afec345dbbad2e0c669b91e1c47d46b0b1d17f0dca298fa28d781e' 
  AND token = 'JJC6JCh2AAIGB5zf438Jq3kLRfB/piXQpdqEJYJXBQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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