SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bffe7aeaf25b4e21293eb5613dbf59828102c4df1bfc81134ee0d732af87c047' 
  AND token = 'dzze6zIOKAQaKv2i6H7rsLV4uHMe6YULpMQ8ueiqWSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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