SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d568d4983ab47dfacd6cbe942041887076b646c9c172e7432219cf7cedbc546' 
  AND token = '3jVOvxx0qG3Mj7cnp1cu1XgH0OoCoWqv+MkF1FCx9PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}