SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9c35dfc74c2f7e498e12ff060dbf3ac972b46ec530d8589393e76a5bcaac269' 
  AND token = 'c1fL6st/llu+2htfkbHxXeYMULDKPlvJbHVmqqc6m8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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