SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50873153f084badf3bf1a369e5d95fab0eb60d8fc5fd8bb7027e3dfa28d9921b' 
  AND token = 'SItcD4hP/p/KzNRPIiE4K/f/KGkZQGS8YF6XHKdQwZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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