SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0780aea1b87be07498a89e69290749f95e9b53e53b9017709e4f03b59c7d46f' 
  AND token = '+e/kgUVaNiIQEFXnYM0YpXYGzndjAGKrZ2MsKwlzzFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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