SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e06c15f950a039f5fea739a93cdfccc54b98c38f18e788fb9ed9e63acaeb4208' 
  AND token = 'f6kMJn88pIBrt3LuS5VKGeF8v0cSLzcWEFVlwwIkknQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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