SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52f776e9c877e97d90463e07e00c47690be2ef204f0921404fc48bb4770a5246' 
  AND token = 'jxnEOA6yFZ2kMLkEowRreav3uG9Ugzk43azwpxumbdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}