SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc9af98d100ca1befeeb30302b14624f6072fe04b059ba22a3c347ad5f43832c' 
  AND token = '2MyszNrKblUYhrT5WCWFlmQKEG+bSftDUrP4BtmTguU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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