SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '243b759cea96c7e13beb6e99289d636b7b4121004d5a422118267910523327d3' 
  AND token = 'RgB/5lrVFaphhUpY3G9qJlam+CMXqgSAeIGmf7/L3/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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