SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9338f8635ad139cc7563b82fa0f0ffe55e795fba0b4d2f0932309416f238c4' 
  AND token = '7AHGbxMjU6JtJ4V9T6yX3yygjxw96lOxWrwcweu95rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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