SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef0f754aaa689b98b4dce156f5a9bc17ef473863645659b27dc991a62e42d835' 
  AND token = 'wCRKQlqV3xNtE1ZWPAE//4oCBYnDh9KwC3siAba+ORk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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