SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2276a7fd598fd1a3b1dad10ed12803830a243479db095eed20c45135cc4f0aac' 
  AND token = 'qidvdE3FDY3fBNRlG/wPfIsfTm8gvyfBETUMiE7Ygyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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