SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02709aaa5950b42715fce4709faa34540a418dfeff27300f3698e268d389d9db' 
  AND token = 'bDbp+9QDb+jlaoGFeooMgd8mn2UXw9EpmqiNX9eW3qk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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