SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '844da22dd3cf603eb977458853d482d6924b5e08d18418afa83e505c39a75cf5' 
  AND token = 'HZ42Nur1KiH0EusmVxHNfpNBCNPJaszrQRt7Ldfy/Pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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