SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1271483c52eba11d3836fc73cc4ef2202b0751f2cd46aa3103822aa0c886c171' 
  AND token = 'xnXy9gpDD9+KSPHQCDh9i/SiJezKyh5fvVGtPRMuAG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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