SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fc52e4144a78e291f30fbf0df960582a9b12bd2020cb431e8517cc86edb33d4' 
  AND token = 'A2h1ZwCGfUfKiTheWUi5QGv4DdjObH+wY506dQabc5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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