SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e09d291bcce66d8cca43cbac1c735b9b07a15b3008f4cfd2308e43e7ecec6c5a' 
  AND token = 'Bc/5pdLznMX76MJYAxDAg2Vhvz+XwqHl7a+QTS4jPxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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