SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc3665712e986174e1d1306672ff24d3260b6cf87572142a18608e774c267f6a' 
  AND token = 'JDZypcPn/MMfHV2hnBdrPuSho7uZC/BhZiZC6UBcFWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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