SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13d9e298757fcb67824b7050a9dc2ba7a57f80f473e0f9b372cb6f810fdae8a4' 
  AND token = 'kuR2+TKvDQlWdTUTEUm0UkjEqRBD9r/Y4kpaGJZhwj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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