SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de75ddfeb13fcb0d2a326be68f263f21031be4796e6144a76369786d51859f55' 
  AND token = '6Ayy1RICKUK5NSyELugZ1oijfkoYlp51jlPcxvNnLjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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