SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b93f240d4743f3ada44e125a40cdfd56b88b2d9306fe60da7b03a21fdbc340a' 
  AND token = 'UGzdYqGF2AnhrBs/2ipooAwjdwjD9g5RQm453isPvhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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