SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcff80ca561077788c1e4edef523daa06ddfe5a3c6227176fe5fd69ab12810c5' 
  AND token = 'szUpthCPLavghYz/6zr2wYkxlNnBPuqvcRRQKGop9RU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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