SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00e53ef3cfa1eff166de98dec4649a438684e2c84b367b9c9401731812eafc3a' 
  AND token = 'tJVwgiM+Dh3UayDTEa2/XEngPluX2aGeg7NqbxOwT5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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