SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2620a07d059a738dd63dcf275d7b758f5c0484ea646b18ffe2522d72a3087a5' 
  AND token = 'nfGUDHGDrhWT8mJXkBeDyRvfjn9dpYUhl/0iv+3rHww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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