SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dd7f6ce6e426ff65157fbd4763cdc983be8d33bff256318f4ff5b5c5f664b12' 
  AND token = 'ksOtdqvJkyGadD9tSELWfF3rmzdAhPskUY21ABtEEtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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