SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a927dc48bb01764b8ebbe17de29db63a906855153d9fb88ce7a81827632aa55' 
  AND token = 'b+XlFE0Y1nWzl3S+6G9If0fplYfU+KTxYxHZpJbmbc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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