SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '951a51dd0dab4bddeb12377c6e54b7af186f82dce700218ae17616d5c01cd0e5' 
  AND token = 'JH1v9seRZ2Qa5cY3FyAHUk40bVCWkMclouN9P/iIgKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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