SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3745a2e14f7e6f879a563c17d2d50c224e650c818c5abde3a15aff24fa61c0d6' 
  AND token = 'XwYpC4r5m8UCr4xTIvgsMNzlTBVNBjGgwGBAPgGjbXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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