SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53e915cd0b5cc10a36313a292ddfdaf1583ddf1082a2f3c677c72664c16e7a25' 
  AND token = 'Y4UJqHJntSAzRQBvRKeYlD5SrFxZjOkJvD4cckjKysI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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