SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '773eb0bc69a0ad76681a126657c3e67637757172a91f7cba85ae691f6fc0eabe' 
  AND token = 'ZtbDWMyUVrnPOcdrUp9/QaVJC/BwAJUhP+yPOwaEjpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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