SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2bc55edb5a9a839bdac738c318082047c9ee402c0c5d5569c8ff97a866897ad' 
  AND token = 'IooNUYxuABf5wiut5ZMGAmX6fFCQpmVIyauna8tiJbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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