SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b775b80e283e527a5378caddeb256fe39c8e65157e94c82d565c606ca5b2567d' 
  AND token = 'hMLQoe2m0tJKHnUuuCPW5DeUMJypByZuQKkxTDC8Mm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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