SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c5b802180cc9f2cdf3220b0237ee6b6385e7b14654c2656397af8bc72fa4659' 
  AND token = 'rF1xTs9LglGIJqMCkY6sB3HrYyHwgeCbqCG3cWEo00w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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