SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b2cbbe0f166ddcca4ad9b34677245442fd2215a0180e6781a273e801ccb0c49' 
  AND token = 'dyjZnvjmRRFmaAZfz6iIEDlXHx92mMG50evyFdprkjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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