SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92d4c17720e8ab094736f721240f8f064a95c79eb18623316561dc2d60de3c5' 
  AND token = 'TPb5oWL6KeEajs8Zafah6clo6MWwGyvXORS6J5hkAtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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