SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a54c6a925900a6b93e3ad2f1bbcc232c877350e98c3565587b192ba8618973' 
  AND token = 'H3vpiA43Cpf/XlVvLMlFkeOsttV4KZeC0QiZCJyY1jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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