SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93b66dbdd54ce449ba070aa285b46b0afef21968fcd47723ca5c954fce8d2ef8' 
  AND token = 'RMVahTjpQCFxBKEkUJap2j35SDmYdoGq2jVRT+Dlf28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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